Bismuth sulfide (BiS) has been of high interest for thermoelectric applications due to the high abundance of sulfur on Earth. However, the low electrical conductivity of pristine BiS results in a low figure of merit (ZT). In this work, BiS@Bi core-shell nanowires with different Bi shell thicknesses were prepared by a hydrothermal method. The core-shell nanowires were densified to Bi/BiS nanocomposite by spark plasma sintering (SPS), and the structure of the nanowire was maintained as the nanocomposite due to rapid SPS processing and low sintering temperature. The thermoelectric properties of bulk samples were investigated. The electrical conductivity of a bulk sample after sintering at 673 K for 5 min using BiS@Bi nanowire powders prepared by treating BiS nanowires in a hydrazine solution for 3 h is 3 orders of magnitude greater than that of a pristine BiS sample. The nanocomposite possessed the highest ZT value of 0.36 at 623 K. This represents a new strategy for densifying core-shell powders to enhance their thermoelectric properties.
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http://dx.doi.org/10.1021/acsami.6b14803 | DOI Listing |
Phys Chem Chem Phys
January 2025
Department of Chemistry, University of Manchester, Oxford Road, Manchester M13 9PL, UK.
An modelling workflow is used to predict the thermoelectric properties and figure of merit of the lanthanide cobalates LaCoO, PrCoO and NdCoO in the orthorhombic phase with the low-spin magnetic configuration. The LnCoO show significantly lower lattice thermal conductivity than the widely-studied SrTiO, due to lower phonon velocities, with a large component of the heat transport through an intraband tunnelling mechanism characteristic of amorphous materials. Comparison of the calculations to experimental measurements suggests the p-type electrical properties are significantly degraded by the thermal spin crossover, and materials-engineering strategies to suppress this could yield improved .
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January 2025
Applied Chemistry and Environmental Science, School of Science, STEM College, RMIT University Melbourne Victoria 3000 Australia
High-temperature reduction of TiO causes the gradual formation of structural defects, leading to oxygen vacancy planar defects and giving rise to Magnéli phases, which are substoichiometric titanium oxides that follow the formula Ti O, with 4 ≤ ≤ 9. A high concentration of defects provides several possible configurations for Ti and Ti within the crystal, with the variation in charge ordered states changing the electronic structure of the material. The changes in crystal and electronic structures of Magnéli phases introduce unique properties absent in TiO, facilitating their diverse applications.
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January 2025
Department of Physics, Riphah International University, Islamabad 44000, Pakistan.
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January 2025
Astronomical Observatory, Jagiellonian University, Orla 171, Krakow, 30-244, Poland.
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View Article and Find Full Text PDFACS Appl Mater Interfaces
January 2025
Hubei Longzhong Laboratory, Wuhan University of Technology, Xiangyang Demonstration Zone, Xiangyang 441000, China.
Materials with both high thermoelectric (TE) performance and excellent magnetocaloric (MC) properties near room temperature are of great importance for all-solid-state TE/MC hybrid refrigeration. A combination of such two critical characteristics, however, is hardly attainable in single phase compounds. Herein we report a composite material that comprises Bi-Sb-Te thermoelectric and Ni-Mn-In magnetocaloric components as an innovative thermoelectromagnetic material with dual functionalities.
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